Pad conditioner and method of conditioning planarization pad

ABSTRACT

A method including rotating a plate of a pad conditioner about an axis parallel to an axis of rotation of a planarization pad of a planarization device. The method further includes dispensing a fluid material onto an upper surface of the planarization pad through a nozzle opening of the pad conditioner during a planarization process, wherein the fluid material comprises an acid. The method further includes maintaining the pad conditioner at a position spaced from the upper surface of the planarization pad during the dispensing of the fluid material and the rotating of the plate.

PRIORITY CLAIM

The present application is a continuation of U.S. application Ser. No.13/948,799, filed Jul. 23, 2013, which is incorporated herein byreference in its entirety.

BACKGROUND

Technological advances in integrated circuit (IC) materials and designhave produced generations of ICs where each generation has smaller andmore complex circuits than the previous generation. However, theseadvances have increased the complexity of processing and manufacturingICs and, for these advances to be realized, similar developments in ICprocessing and manufacturing are needed. For example, planarizationtechnology, such as a chemical mechanical polishing (CMP) process, hasbeen implemented to planarize a substrate or one or more layers offeatures over the substrate. A material removal rate for a CMP processvaries according to various factors, including roughness of an uppersurface of a planarization pad in a planarization device where the CMPprocess takes place.

DESCRIPTION OF THE DRAWINGS

One or more embodiments are illustrated by way of example, and not bylimitation, in the figures of the accompanying drawings, whereinelements having the same reference numeral designations represent likeelements throughout.

FIG. 1 is a cross-sectional view of a portion of a planarization devicehaving a semiconductor wafer therewithin in accordance with one or moreembodiments.

FIG. 2 is an enlarged view of region A in FIG. 1 in accordance with oneor more embodiments.

FIGS. 3A-3H are diagrams of various patterns of nozzle openings inaccordance with one or more embodiments.

FIG. 4 is a flow chart of a method of reconditioning a planarization padin accordance with one or more embodiments.

DETAILED DESCRIPTION

It is understood that the following disclosure provides one or moredifferent embodiments, or examples, for implementing different featuresof the disclosure. Specific examples of components and arrangements aredescribed below to simplify the present disclosure. These are, ofcourse, examples and are not intended to be limiting. In accordance withthe standard practice in the industry, various features in the drawingsare not drawn to scale and are used for illustration purposes only.

Moreover, spatially relative terms, for example, “lower,” “upper,”“horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top,”“bottom,” “left,” “right,” etc. as well as derivatives thereof (e.g.,“horizontally,” “downwardly,” “upwardly,” etc.) are used for ease of thepresent disclosure of one features relationship to another feature. Thespatially relative terms are intended to cover different orientations ofthe device including the features.

In accordance with the present application, in at least one embodiment,a pressurized fluid material is dispensed onto a planarization pad of aplanarization device for maintaining the roughness of the planarizationpad and for removing residues on the planarization pad, which aresometimes collectively referred to as reconditioning the planarizationpad. Compared with another configuration using diamond plate forreconditioning, using pressurized fluid material reduces the scratchdefects on a CMP-processed wafer caused by cracked diamonds.

FIG. 1 is a cross-sectional view of a portion of a planarization device100 having a semiconductor wafer 110 therewithin in accordance with oneor more embodiments. Planarization device 100 includes a platform 120, aplanarization pad 130 over platform 120, a wafer holder 140 overplatform 120 and holding wafer 110, a pad conditioner 150 overplanarization pad 130, and a slurry dispenser 160 over platform 120.Planarization pad 130 has an upper surface 132 and grooves 134, and thegrooves 134 have bottom surfaces lower than the upper surface 132. Theupper surface 132 of the planarization pad 130 defines a reference planein parallel with X direction and Y direction (a direction into the page,not shown). In some embodiments, the wafer 110 is a semiconductor waferhaving a surface 112 to be processed by a planarization process. Duringa period that planarization device 100 is operated to perform aplanarization process, such as a CMP process, a layer of slurry material172 is over the planarization pad 130, filling the grooves 134, and incontact with upper surface 132 of planarization pad 130 and surface 112of wafer 110.

Wafer holder 140 includes a robot arm 142 and a clamper 144 rotatablymounted to the robot arm. In some embodiments, robot arm 142 includes adriving unit configured to move clamper 144 along a direction parallelto the upper surface 132 of planarization pad 130. In some embodiments,robot arm 142 and/or clamper 144 include a driving unit configured tocause clamper 144 to rotate according to a first predeterminedrotational-speed profile. In some embodiments, the first predeterminedrotational-speed profile includes a rotational speed ranging from 0 to200 revolutions per minute (rpm).

Pad conditioner 150 includes a robot arm 152 and a plate 154 rotatablymounted to the robot arm. In some embodiments, robot arm 152 includes adriving unit configured to move plate 154 along a direction parallel tothe upper surface 132 of planarization pad 130. In some embodiments,robot arm 152 and/or clamper 154 include a driving unit configured tocause plate 154 to rotate according to a second predeterminedrotational-speed profile. In some embodiments, the second predeterminedrotational-speed profile includes a rotational speed ranging from 40 rpmto 300 rpm. In at least one embodiment, the platform 120 is alsorotatable.

Slurry dispenser 160 delivers a slurry material 174 onto upper surface132 of the planarization pad 130 to form the layer of slurry material172. In some embodiments, the layer of slurry material 172 includes asolution containing etchant and/or polishing grit.

During operation of the planarization device 100, the wafer holder 140and the planarization pad 130 are movable with respect to each other.The layer of slurry material 172 chemically etching and mechanicallyabrading the surface 112 of the wafer 110 in order to planarize (alsobeing referred to as “polish”) the surface 112 of the wafer 110 at apredetermined removal rate.

In some embodiments, the upper surface 132 of the planarization pad 130is prepared to have a predetermined range of roughness. However, duringoperation of the planarization device 100, the upper surface 132 of theplanarization pad 130 becomes smoother. In order to keep the roughnessof the upper surface 132 within the predetermined range, pad conditioner150 is usable to scratch the upper surface 132 of the planarization pad130 in order to maintain the roughness of the upper surface 132 and toremove any residues formed on the upper surface 132.

The plate 154 of pad conditioner 150 has a lower surface 156 separatedfrom upper surface 132 of the planarization pad 130 by a predetermineddistance D (FIG. 2) and one or more nozzle openings on the lower surface156 of the plate 154. A fluid material 158 is dispensed onto uppersurface 132 of the planarization pad 130 through the one or more nozzleopenings in order to recondition the planarization pad. In someembodiments, the reconditioning of the upper surface 132 of theplanarization pad 130 is performed during the polishing of the surface112 of the wafer 110 or before or after the polishing of the surface112.

FIG. 2 is an enlarged view of region A in FIG. 1 in accordance with oneor more embodiments. One or more nozzle openings 210 are disposed on alower surface of plate 154. The lower surface 156 of the plate 154 andthe upper surface 132 of the planarization pad 130 are separated by apredetermined distance D. In some embodiments, the predetermineddistance D ranges from 0.1 to 250 millimeters (mm).

A fluid dispensing unit 220 is coupled with the one or more nozzleopenings 210 through a conduit system 230. In some embodiments, conduitsystem 230 includes a network of tubes passing though the robot arm 152,a rotational axel 240 connecting the plate 154 and robot arm 152, and/orembedded inside the plate 154. Fluid dispensing unit 220 is configuredto dispense the fluid material 158 onto the upper surface 132 of theplanarization pad 130 through the one or more nozzle openings 210. Insome embodiments, fluid dispensing unit 220 is mounted on the robot arm152. In some embodiments, fluid dispensing unit 220 is disposedseparately from the robot arm 152.

In some embodiments, fluid dispensing unit 220 is configured to dispensethe fluid material 158 at a predetermined spray pressure at the one ormore nozzle openings 210. In some embodiments, the predeterminedpressure is set to be sufficient to remove residues on the planarizationpad 130. In some embodiments, the predetermined pressure is set to besufficient to restore the roughness of the upper surface 132 of theplanarization pad 130.

In some embodiments, the predetermined spray pressure ranges from 0.1pounds per square inch (PSI) to 20 PSI. In some embodiments, fluiddispensing unit 220 and the one or more nozzle openings are configuredto dispense the fluid material 158 at a predetermined spray angle θ atone of the one or more nozzle openings, and the predetermined sprayangle θ ranges from 0 degree to 45 degrees with respect to Z direction,which is perpendicular to the upper surface 132 of the planarizationpad. A non-zero degree spray angle helps to wash residues out of thegrooves 134 and restore the roughness of the upper surface 132. In someembodiments, the reconditioning of planarization pad 130 is primarilybased on a downward (i.e., along the negative Z direction) force to“grind” the upper surface 132 by pressurized fluid material. Thus, ifthe spray angle is greater than 45 degrees, the reconditioning ofplanarization pad 130 would be less power-efficient.

In some embodiments, the fluid material 158 includes a slurry materialwhen the fluid dispensing unit 220 is operated during a planarizationprocess performed by the planarization device 100 (FIG. 1). In someembodiments, the fluid material 158 includes water, de-ionized water,NH₄OH based solution, HF based solution, KOH based solution, or citricacid based solution, silica based solution, cerium based solution, orhydrous solution having a water weight percentage greater than 20%, whenthe fluid dispensing unit 220 is operated before or after aplanarization process performed by the planarization device 100.

Various patterns of nozzle openings are illustrated in conjunction withFIGS. 3A-3H.

FIG. 3A is a diagram of a first example pattern of nozzle openings 320a-320 d in accordance with one or more embodiments. Nozzle openings 320a-320 d are on the lower surface 156 of the plate and arranged in aradially symmetrical manner about a rotational center 310 of therotatable plate. In the example depicted in FIG. 3A, nozzle openings 320a and 320 c are positioned along a line crossing the rotational center310, and nozzle openings 320 b and 320 d are positioned along anotherline crossing the rotational center 310.

FIG. 3B is a diagram of a second example pattern of nozzle openings 330in accordance with one or more embodiments. Nozzle openings 330 are onthe lower surface 156 of the plate and arranged in a circularlysymmetrical manner about the rotational center 310 of the rotatableplate. In the example depicted in FIG. 3B, nozzle openings 330 arepositioned along a peripheral of a circle having a center coincidingwith the rotational center 310.

FIG. 3C is a diagram of a third example pattern of nozzle openings 340a-340 c in accordance with one or more embodiments. Nozzle openings 340a-340 c are on the lower surface 156 of the plate and arranged in acircularly symmetrical manner about the rotational center 310 of therotatable plate. In the example depicted in FIG. 3C, nozzle openings 340a, 340 b, and 340 c are positioned along peripherals of correspondingcircles having centers coinciding with the rotational center 310. Inother words, nozzle openings 340 a, 340 b, and 340 c are positionedalong peripherals of concentric circles about the rotational center 310.

FIG. 3D is a diagram of a fourth example pattern of nozzle openings 350a-350 c in accordance with one or more embodiments. Nozzle openings 350a-350 c are on the lower surface 156 of the plate. Nozzle openings 350 ahave a geographic center 352 a, nozzle openings 350 b have a geographiccenter 352 b, and nozzle openings 350 c have a geographic center 352 c.The geographic centers 352 a-352 c of nozzle openings 350 a-350 c arearranged in a radially symmetrical manner or a circularly symmetricalmanner about the rotational center 310 of the plate.

FIGS. 3E-3G are diagrams of additional example patterns of nozzleopenings 360, 370, and 380 in accordance with one or more embodiments.Nozzle openings 360, 370, and 380 are on the lower surface 156 of theplate and positioned along at least one polygon, such as a triangle(360), a square or rectangle (370), a pentagon (380), or an ellipse (notshown), or any other suitable shapes. Although only one polygon isdepicted in FIG. 3E, 3F, or 3G, in some embodiments, nozzle openings arearranged according to one or more of the same polygon of a differentsize or different polygons, circles, or ellipses of various sizes.

FIG. 3H is a diagram of yet another example pattern of nozzle openings390 in accordance with one or more embodiments. Nozzle openings 390 areon the lower surface 156 of the plate and evenly distributed on thelower surface of the plate. In at least one embodiment, nozzle openings390 are randomly distributed on the lower surface 156 of the plate.

The patterns of nozzle openings depicted in FIGS. 3A-3H are merelyexamples. In some embodiments, nozzle openings are positioned accordingto other suitable patterns. In some embodiments, nozzle openings have ageographic center substantially coinciding with the rotational center ofthe plate.

FIG. 4 is a flow chart of a method 400 of reconditioning a planarizationpad in accordance with one or more embodiments. It is understood thatadditional operations may be performed before, during, and/or after themethod 400 depicted in FIG. 8, and that some other processes may only bebriefly described herein.

As depicted in FIG. 4 and FIG. 1, in operation 410, a driving unitcauses a plate 154 of a pad conditioner 150 to rotate according to apredetermined rotational-speed profile. In some embodiments, thepredetermined rotational-speed profile includes a rotational speedranging from 40 rpm to 300 rpm.

As depicted in FIG. 4 and FIGS. 1-2, in operation 420, a fluiddispensing unit 220 dispenses a fluid material 158 onto an upper surface132 of a planarization pad 150 of a planarization device 100 throughnozzle openings 210 disposed on a lower surface 156 of the plate 154. Insome embodiments, the dispensing the fluid material includes dispensingthe fluid material 158 at a predetermined spray pressure at the nozzleopenings 210. In some embodiments, the predetermined spray pressureranges from 0.1 PSI to 20 PSI. In some embodiments, the dispensing thefluid material includes dispensing the fluid material 158 at apredetermined spray angle θ at the nozzle openings 210. In someembodiments, the predetermined spray angle θ ranges from 0 degree to 45degrees with respect to Z direction, which is perpendicular to the uppersurface 132 of the planarization pad 130.

In some embodiments, the dispensing the fluid material further includesdispensing a slurry material during a period the planarization pad 130is operated to perform a planarization process. In some embodiments, thedispensing the fluid material further includes dispensing water,de-ionized water, NH₄OH based solution, HF based solution, KOH basedsolution, or citric acid based solution, silica based solution, ceriumbased solution, or hydrous solution having a water weight percentagegreater than 20%, during a period before or after the planarization pad130 is operated to perform a planarization process.

An aspect of this description relates to a method including rotating aplate of a pad conditioner about an axis parallel to an axis of rotationof a planarization pad of a planarization device. The method furtherincludes dispensing a fluid material onto an upper surface of theplanarization pad through a nozzle opening of the pad conditioner duringa planarization process, wherein the fluid material comprises an acid.The method further includes maintaining the pad conditioner at aposition spaced from the upper surface of the planarization pad duringthe dispensing of the fluid material and the rotating of the plate. Insome embodiments, the dispensing the fluid material further includesdispensing the fluid material at a predetermined spray pressure at thenozzle openings, the predetermined spray pressure ranging from 0.1pounds per square inch (PSI) to 20 PSI. In some embodiments, thedispensing the fluid material further includes dispensing the fluidmaterial at a predetermined spray angle at the nozzle openings, thepredetermined spray angle ranging from 0 degrees to 45 degrees withrespect to a direction perpendicular to the upper surface of theplanarization pad. In some embodiments, the dispensing the fluidmaterial further includes dispensing a slurry material during a periodthe planarization pad is operated to perform the planarization process.In some embodiments, dispensing the fluid material further includesdispensing one or more of water, de-ionized water NH₄OH based solution,KOH based solution, silica based solution, cerium based solution, orhydrous solution having a water weight percentage greater than 20%,during a period before or after the planarization pad is operated toperform the planarization process. In some embodiments, dispensing thefluid material includes dispensing the acid comprising at least one ofan HF based solution or a citric acid based solution. In someembodiments, dispensing the fluid material includes dispensing the fluidmaterial from a plurality of nozzles. In some embodiments, dispensingthe fluid material includes dispensing the fluid material from aplurality of nozzles arranged in a concentric pattern. In someembodiments, dispensing the fluid material comprises dispensing thefluid material from a plurality of nozzles arranged in a circularpattern. In some embodiments, dispensing the fluid material includesdispensing the fluid material from a plurality of nozzles arranged alongtwo intersecting lines. In some embodiments, dispensing the fluidmaterial includes dispensing the fluid material from a plurality ofnozzles arranged in a polygonal pattern.

An aspect of this description relates to a planarization device. Theplanarization device includes a planarization pad; and a pad conditionerover the planarization pad. The pad conditioner includes a rotatableplate having a lower surface separated from an upper surface of theplanarization pad by a predetermined distance. The pad conditionerfurther includes a plurality of nozzle openings on the lower surface ofthe rotatable plate. The pad conditioner further includes a fluiddispensing unit configured to selectively dispense a fluid material ontothe upper surface of the planarization pad through the plurality ofnozzle openings based on an operating mode of the planarization device,wherein the fluid material comprises an acid, and the pad conditioner isconfigured to maintain at least the predetermined distance between thelower surface of the rotatable plate and the upper surface of theplanarization pad during dispensing of the fluid material. In someembodiments, the planarization device further includes a slurrydispenser for dispensing a slurry onto the planarization pad, whereinthe slurry dispenser is spaced from the pad conditioner. In someembodiments, the plurality of nozzles is arranged in a concentricpattern. In some embodiments, the plurality of nozzles is arranged in acircular pattern. In some embodiments, the plurality of nozzles isarranged along two intersecting lines. In some embodiments, theplurality of nozzles is arranged in a polygonal pattern.

An aspect of this description relates to a method including dispensing aslurry onto a planarization pad. The method further includes rotatingthe planarization pad about a first axis. The method further includesrotating a plate of a pad conditioner about an axis parallel to thefirst axis. The method further includes dispensing a fluid material ontoan upper surface of the planarization pad through a plurality of nozzleopenings of the pad conditioner during the rotation of the planarizationpad, wherein the fluid material comprises an acid. The method furtherincludes maintaining the pad conditioner at a position spaced from theupper surface of the planarization pad during the dispensing of thefluid material and the rotating of the plate. In some embodiments,dispensing the fluid material includes dispensing the fluid materialduring the dispensing of the slurry. In some embodiments, dispensing thefluid material includes dispensing the fluid material during a periodbefore or after the planarization pad is operated to perform aplanarization process.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method comprising: rotating a plate of a padconditioner about an axis parallel to an axis of rotation of aplanarization pad of a planarization device; dispensing a fluid materialonto an upper surface of the planarization pad through a nozzle openingof the pad conditioner during a planarization process, wherein the fluidmaterial comprises an acid; maintaining the pad conditioner at aposition spaced from the upper surface of the planarization pad duringthe dispensing of the fluid material and the rotating of the plate. 2.The method of claim 1, wherein the dispensing the fluid material furthercomprises: dispensing the fluid material at a predetermined spraypressure at the nozzle openings, the predetermined spray pressureranging from 0.1 pounds per square inch (PSI) to 20 PSI.
 3. The methodof claim 1, wherein the dispensing the fluid material further comprises:dispensing the fluid material at a predetermined spray angle at thenozzle openings, the predetermined spray angle ranging from 0 degrees to45 degrees with respect to a direction perpendicular to the uppersurface of the planarization pad.
 4. The method of claim 1, wherein thedispensing the fluid material further comprises dispensing a slurrymaterial during a period the planarization pad is operated to performthe planarization process.
 5. The method of claim 1, wherein dispensingthe fluid material further comprises dispensing one or more of water,de-ionized water NH₄OH based solution, KOH based solution, silica basedsolution, cerium based solution, or hydrous solution having a waterweight percentage greater than 20%, during a period before or after theplanarization pad is operated to perform the planarization process. 6.The method of claim 1, wherein dispensing the fluid material comprisesdispensing the acid comprising at least one of an HF based solution or acitric acid based solution.
 7. The method of claim 1, wherein dispensingthe fluid material comprises dispensing the fluid material from aplurality of nozzles.
 8. The method of claim 1, wherein dispensing thefluid material comprises dispensing the fluid material from a pluralityof nozzles arranged in a concentric pattern.
 9. The method of claim 1,wherein dispensing the fluid material comprises dispensing the fluidmaterial from a plurality of nozzles arranged in a circular pattern. 10.The method of claim 1, wherein dispensing the fluid material comprisesdispensing the fluid material from a plurality of nozzles arranged alongtwo intersecting lines.
 11. The method of claim 1, wherein dispensingthe fluid material comprises dispensing the fluid material from aplurality of nozzles arranged in a polygonal pattern.
 12. Aplanarization device, comprising: a planarization pad; and a padconditioner over the planarization pad, the pad conditioner comprising:a rotatable plate having a lower surface separated from an upper surfaceof the planarization pad by a predetermined distance; a plurality ofnozzle openings on the lower surface of the rotatable plate; and a fluiddispensing unit configured to selectively dispense a fluid material ontothe upper surface of the planarization pad through the plurality ofnozzle openings based on an operating mode of the planarization device,wherein the fluid material comprises an acid, and the pad conditioner isconfigured to maintain at least the predetermined distance between thelower surface of the rotatable plate and the upper surface of theplanarization pad during dispensing of the fluid material.
 13. Theplanarization device of claim 12, further comprising a slurry dispenserfor dispensing a slurry onto the planarization pad, wherein the slurrydispenser is spaced from the pad conditioner.
 14. The planarizationdevice of claim 1, wherein the plurality of nozzles is arranged in aconcentric pattern.
 15. The planarization device of claim 1, wherein theplurality of nozzles is arranged in a circular pattern.
 16. Theplanarization device of claim 1, wherein the plurality of nozzles isarranged along two intersecting lines.
 17. The planarization device ofclaim 1, wherein the plurality of nozzles is arranged in a polygonalpattern.
 18. A method comprising: dispensing a slurry onto aplanarization pad; rotating the planarization pad about a first axis;rotating a plate of a pad conditioner about an axis parallel to thefirst axis; dispensing a fluid material onto an upper surface of theplanarization pad through a plurality of nozzle openings of the padconditioner during the rotation of the planarization pad, wherein thefluid material comprises an acid; maintaining the pad conditioner at aposition spaced from the upper surface of the planarization pad duringthe dispensing of the fluid material and the rotating of the plate. 19.The method of claim 18, wherein dispensing the fluid material comprisesdispensing the fluid material during the dispensing of the slurry. 20.The method of claim 18, wherein dispensing the fluid material comprisesdispensing the fluid material during a period before or after theplanarization pad is operated to perform a planarization process.